1. Field of the Invention
The present invention relates to a process for treating livestock wastewater streams, lagoon water systems, sludges, and the like. The treatment contemplated by this invention is particularly applicable to wastes derived from slaughterhouses, fancy meat departments, and tank houses. The instant method is particularly applicable for reducing odors and contaminants from multi-animal wastewater sources. Current government regulations require that such waste contaminants must be removed from the wastewater, or collected in storage so as to be in compliance with the regulations. The Environmental Protection Agency (EPA) has recently issued very stringent effluent guidelines and standards for hog and poultry industries in particular.
The food processing industries such as the hog industry, poultry industry, slaughter-houses, fish meal factories and bone meal factories typically consume large quantities of water in the various processing segments of their plants, which water is then discharged as wastewater. This water and/or wastewater, contains large quantities of fats and oils, fatty acids, proteinaceous material, blood, and other undesirable solids.
The large amounts of blood, fats and oils, proteinaceous materials and dissolved organic material raise the total ammonia and nitrogen content of the water, thereby increasing the level of stench and the septicity of the animal waste. Therefore the water used in the various plants sections becomes contaminated with a number of obnoxious substances. The effluent may vary in composition but typical effluent from an abattoir, hog farm or poultry processing plant contains appreciable amounts of blood proteins, soluble protein from muscle and tissues, suspended or colloidal protein material, fragmented tissue and fat.
At the present time most of the effluents from animal waste derived from farms or slaughterhouses are usually treated by microbiological methods (i.e., both aerobic and anaerobic) in holding tanks. The two disadvantages of this method are that a large area of ground is required for the equipment and the processing area holding tanks and that the process destroys the potentially valuable proteins. The result is generally foul smelling wastewater that has over 1,000 parts per million (ppm) of total ammonia, over 1,000 ppm of total nitrogen, over 100,000 mg./l. Biological Oxygen Demand (BOD), over 200,000 ppm Chemical Oxygen Demand (COD), over 50,000 ppm of Total Suspended Solids (TSS), and over 30,000 ppm of Oil and Grease (O&G). These levels may vary from plant to plant.
2. Description of the Prior Art
The patent literature reveals that a number of systems have been proposed for clarification of industrial waste effluent of various types of animal waste. For example, in U.S. Pat. No. 5,807,587, Cox et. al. disclose a composition and method for preventing and/or reducing stench and septicity from animal waste comprising the use of a sulfur and oxygen-bearing component, one or more aldehydes (e.g. formaldehyde) and/or one or more ketones, and surfactant. The use of such compositions has serious impact on threshold limits. The aldehyde and ketone vapors and/or mist are intensely irritating agents to humans and contribute to increases in the COD and BOD levels. The disclosure of U.S. Pat. No. 5,807,587 is incorporated herein by reference.
Miller in U.S. Pat. No. 5,174,903 teaches a process for the recovery of proteinaceous materials, fats and oils from wastewater by using lignin as coagulant, a natural polymer polysaccharide such as carboxymethylhydroxypropyl substituted guar gums, synthetic polymer, and chlorine gas or sodium hypochlorite. The chlorine or sodium hypochlorite alone in such as process facilitates the formation of toxic chloroamines, increases the threshold limits, and does not solve the problem of high level effluent purification with the elimination of the high percentage of ammonia (NH3-N). The '903 patent relates in particular to protein recovery. It also does not solve the problems of treating and/or removing contaminants from the wastewater stream which will be discharged. The '903 patent disclosure is incorporate herein by reference.
Waldmann in U.S. Pat. No. 5,238,575 (Filed Feb. 4, 1991) describes the use of an siliceous vulco clay modified by a hydrophobic long chain alkyl (C12-C24, preferably &gt;C16) amines protonized by an aliphatic acid (C1-18) to remove odor and liquid hydrocarbon contaminants in a water stream. The described chemical absorbents comprises products of a formula of AmBnCp wherein A, B and C are an siliceous volclay, or attapulgite clay, a hydrous silicate of aluminum generated from sodium bentonite or calcium bentonite, or monmorillonite bentonite, a modified aminoplast resin, and a siliceous support-modified hydrophobic material respectively. The '575 disclosure is incorporated herein by reference.
An aspect of the present invention is that other organophilic clay which may be employed are primary, secondary, tertiary, and quaternary substituted ammonium salts of montmorillonite, hectorite, attapulgite, sepiolite, and smectite in which the substituted ammonium cation or phosphonium cation contains at least one carbon chain of 12 or more carbon atoms in length. These organoclays are used in general as thickener agents. The chemically modified forms of the present invention are well-known materials and commercially available. Preferred are the powder forms with smaller particles having low density (Specific Gravity), preferably less than one (1), for use at from 1% to 15% by weight of the wastewater contaminant solids.
Example of the technologies using water-swellable clays are disclosed in the:
U.S. Pat. No. 5,401,418 issued to Boyd (filed Aug. 10, 1993) PA1 U.S. Pat. No. 5,302,570 issued to Newman (filed Nov. 2, 1992) PA1 U.S. Pat. No. 5,266,208 issued to Stahley, et. al. (filed May 29, 1992) PA1 U.S. Pat. No. 5,268,109 issued to Boyd (filed Mar. 15, 1993) PA1 U.S. Pat. No. 5,151,155 issued to Cody, et. al.(filed May 9, 1991) PA1 U.S. Pat. No. 4,517,094 issued to Beall (filed Jun. 28, 1983) PA1 U.S. Pat. No. 4,287,086 issued to Finlayson, et. al. (filed Dec. 10, 1976) PA1 U.S. Pat. No. 4,105,578 issued to Finlayson, et. al. (filed Feb. 23, 1977) PA1 U.S. Pat. No. 3,974,125 issued to Oswald, et. al. (filed Sep. 27, 1974) PA1 U.S. Pat. No. 3,422,185 issued to Kuritzef PA1 U.S. Pat. No. 2,966,506 issued to Jordan
These references relate to the well-known art of organoclays having the Specific Gravity range of 1.2 to 2.5. None of these aforementioned references teach or suggest the use organoclays to remove contaminants and odor from livestock wastewater nor from livestock water streams. In contrast, the organoclays in the present invention act as absorbents, and adsorbants provide assistance to the coagulation system used, act as neutralizing charged density agents, and act as precipitating agents of the contaminated matter. These above listed patents are incorporated herein by reference.
In U.S. Pat. No. 5,795,480 (filed Dec. 30, 1996) Keun, et. al. teach a method and system for the treatment of the livestock wastewater by a biodegradation. The '480 disclosure is incorporated herein by reference.
In U.S. Pat. No. 4,409,925 Brundrett, et. al. describe an absorbent suitable for a wide variety of uses including for selective absorption of water or animal waste. The absorbent usually consists of Plaster of Paris in combination with other components. The '925 disclosure does not teach or suggest the use of the absorbent to suppress odor or treat livestock wastewater. The '925 disclosure is incorporated herein by reference.
O'Neill, et. al., in U.S. Pat. No. 3,966,450 teach controlling the odor of animal waste slurry by contacting the waste slurry with hydrogen peroxide, adjusting the pH with a mineral acid, and mixing the slurry until the odor in no longer objectionable. The '450 disclosure is incorporate herein by reference.
Cox, et. al., in U.S. Pat. Nos. 5,609,863 and 5,807,587 disclose compositions and methods for reducing odor and septicity by use of one or more aldehydes and/or one or more ketones along with other compounds. '587 also discloses the use of a sulfur and oxygen bearing component which is selected from the group of sulfites, metabisulfites, lithium hydrosulfite, and the like. Neither '863 nor '587 teach or suggest that the methods described eliminate the water contaminants. The disclosures of '869 and '587 are incorporated herein by reference.